Windows Shared Memory (shmop) errno Handling #21103
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Add proper errno setting for all error paths in shmget() on Windows. Introduces tsrm_set_errno_from_win32_error() to map Windows error codes to POSIX errno values (EACCES, ENOMEM, EINVAL, EEXIST, ENOENT). This ensures that shmop_open() can provide meaningful error messages to users instead of "No error" when operations fail. Tests added to verify errno mapping for different error conditions.
Set errno for error conditions in shmdt() and shmctl(): - EINVAL for invalid segment address/key - Windows error mapping for UnmapViewOfFile failures - EINVAL for unknown shmctl commands This completes errno handling for all shmop system calls on Windows.
Add proper handle cleanup when marking shared memory segment for deletion. Previously, shmctl(IPC_RMID) only marked the segment by setting key to -1 but did not close the Windows file mapping handle, causing the segment to persist in the system. This led to errors when trying to reopen segments with the same key: - Segment remained accessible via OpenFileMapping() - But had key = -1, failing validation checks - Resulted in "Invalid argument" errors Now properly closes the handle, allowing Windows to destroy the named mapping object when no processes are attached, matching POSIX semantics where IPC_RMID marks segment for deletion. Fixes issue where shmop_open() with 'c' flag fails after shmop_delete().
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Problem
On Windows, the
shmopextension functions (shmop_open,shmop_delete, etc.) were not settingerrnoproperly when operations failed. This resulted in unhelpful error messages like"No error"instead of meaningful diagnostics.Additionally,
shmctl(IPC_RMID)did not properly close the Windows file mapping handle, causing shared memory segments to persist even after deletion.Solution
1. Windows-to-POSIX errno Mapping (
tsrm_win32.c)Introduced
tsrm_set_errno_from_win32_error()function that converts Windows error codes to POSIX errno values:ERROR_ACCESS_DENIEDEACCESERROR_NOT_ENOUGH_MEMORY,ERROR_OUTOFMEMORYENOMEMERROR_INVALID_PARAMETER,ERROR_INVALID_HANDLEEINVALERROR_ALREADY_EXISTSEEXISTERROR_FILE_NOT_FOUND,ERROR_PATH_NOT_FOUNDENOENT2. errno Set in All Error Paths
shmget():EINVAL— invalid size (0 or overflow)EEXIST— segment exists whenIPC_EXCLflag is setENOMEM— failed to allocate internal structureCreateFileMapping/OpenFileMappingfailuresshmdt():EINVAL— invalid segment addressUnmapViewOfFilefailuresshmctl():EINVAL— invalid key or unknown command3. Proper Handle Cleanup in
IPC_RMIDWhen
shmctl(IPC_RMID)is called and no processes are attached, the Windows file mapping handle is now properly closed withCloseHandle(). This allows Windows to destroy the named mapping object, matching POSIX semantics whereIPC_RMIDmarks the segment for deletion.Files Changed
TSRM/tsrm_win32.c— Core implementationTests Added
ext/shmop/tests/shmop_errno_codes_win32.phptext/shmop/tests/shmop_errno_mapping_win32.phptext/shmop/tests/shmop_errno_tests.phptext/shmop/tests/shmop_error_conditions_win32.phptResult
Error messages are now meaningful:
Unable to attach or create shared memory segment "No error"Unable to attach or create shared memory segment "File exists"